WO2018153202A1

WO2018153202A1 - Data caching method and apparatus

Info

Publication number: WO2018153202A1
Application number: PCT/CN2018/073965
Authority: WO
Inventors: 张广艳; 杨洪章; 吴桂勇; 罗圣美
Original assignee: 中兴通讯股份有限公司
Priority date: 2017-02-21
Filing date: 2018-01-24
Publication date: 2018-08-30
Also published as: CN108459821B; US11226898B2; CN108459821A; EP3588913A4; EP3588913A1; US20210133103A1; EP3588913B1

Abstract

Disclosed in the present invention is a data caching method and apparatus, the data caching method comprising the following steps: receiving a data request message sent by a user terminal; if detecting that a cache apparatus does not comprise the target access data requested by the data request message, then sending the target access data in a storage apparatus to the user terminal; extracting parameter information of the target access data in the storage apparatus, and determining whether the parameter information matches a preset parameter condition; and, if the parameter information matches the preset parameter condition, then transmitting the target access data to the cache apparatus.

Description

Data buffering method and device

Technical field

The present invention relates to the field of data storage technologies, and in particular, to a data caching method and a data caching device.

Background technique

A distributed storage system is composed of a plurality of storage devices, a cache device, and an input/output (I/O) bus, and each storage device performs data transmission through an I/O bus, and is based on data between the storage devices. Decentralized layout enables efficient and inexpensive data storage, and distributed storage systems are widely used in intensive computing and cloud computing due to their powerful scalability.

The conventional data caching method applied to a distributed storage system mainly adopts an on-demand policy, that is, if it is detected that there is no data required by the user in the cache device, the data stored in the storage device is loaded. Go to the cache device in response to the needs of the user terminal. However, due to the limited capacity of the cache device, the data transferred into the cache device during the above response process replaces other data of the cache device, and there is also a problem that since the new call-in buffer device is no longer accessed in the subsequent process. The data or access times are small but multiple accesses to the replaced data are required, so the newly loaded data will occupy the storage resources in the cache device so that the storage resources cannot be fully utilized. In addition, due to the large cache size in the distributed storage mode, the buffer operation on the data block requires a large amount of network bandwidth and storage read and write overhead. Therefore, the data caching method applied to the distributed storage system has a problem that the storage resource utilization rate is low.

Summary of the invention

The invention provides a data buffering method and a data buffering device.

According to an embodiment of the present invention, a data caching method is provided, the method comprising the steps of: receiving a data request message sent by a user terminal; if detecting that the caching device does not include the target access data requested by the data request message, Transmitting, to the user terminal, the target access data in the storage device; extracting parameter information related to the target access data in the storage device, and determining whether the parameter information matches a preset parameter condition; And if the parameter information matches a preset parameter condition, transmitting the target access data to the cache device.

In some embodiments, the parameter information includes an access number; and, if the parameter information matches the preset parameter condition, transmitting the target access data to the cache device comprises: if The number of accesses is greater than or equal to a preset first threshold, and the target access data is transmitted to the cache device.

In some embodiments, the parameter information includes an access number and an access time, and if the parameter information matches the preset parameter condition, the step of transmitting the target access data to the cache device comprises: if The target access data is transmitted to the cache device when the number of accesses is greater than or equal to a preset second threshold and the access time is within a preset period.

In some embodiments, after the step of transmitting the target access data to the cache device, the method further comprises: detecting a cache occupancy rate of the cache device; and if the cache occupancy rate is greater than or equal to a preset And a third threshold, the data of the access times in the cache device being less than or equal to a preset fourth threshold is cleared and/or the modified data in the cache device is transmitted to the storage device.

In some embodiments, after the step of receiving the data request message sent by the user terminal, the method further includes: redundantly backing up the cache information in the memory of the cache device to the persistent storage device of the cache device; And if it detects that a node failure or a system crash occurs in the cache device, restoring cached information in the cache device to the cache device.

In some embodiments, after the step of transmitting the target access data to the cache device, the method further comprising: if detecting that the cache device includes the target access data requested by the data request message, The user terminal transmits the target access data in the cache device.

In accordance with another embodiment of the present invention, a computer readable medium storing program instructions for causing a computer to perform the data caching method described above is provided.

According to another embodiment of the present invention, a data cache device is provided. The data cache device includes: a receiving module configured to receive a data request message sent by the user terminal; and a sending module configured to detect that the cache device does not include the Transmitting, by the data request message, the target access data, the target access data in the storage device to the user terminal; and the extracting module configured to extract parameter information related to the target access data in the storage device And determining whether the parameter information matches a preset parameter condition; and the transmitting module is configured to transmit the target access data to the cache device if the parameter information matches the preset parameter condition.

In some embodiments, the parameter information includes a number of accesses; and the preset parameter condition is that the number of accesses is greater than or equal to a preset second threshold.

In some implementations, the parameter information includes an access number and an access time; and the preset parameter condition is: the access times are greater than or equal to a preset second threshold, and the access time is within a preset period. .

In some embodiments, the data caching device further includes: a detecting module configured to detect a cache occupancy rate of the caching device; and a processing module configured to: if the buffer occupancy rate is greater than or equal to a preset third threshold And clearing data in the cache device that is less than or equal to a preset fourth threshold and/or transmitting the modified data in the cache device to the storage device.

In some embodiments, the data caching device further includes: a backup module configured to redundantly back up cache information in the memory of the cache device to the persistent storage device of the cache device; and a recovery module configured to If it is detected that a node failure or a system crash occurs in the cache device, the cached information in the cache device is restored to the cache device.

In some embodiments, the sending module is further configured to: if the cache device is detected to include the target access data requested by the data request message, send the location in the cache device to the user terminal The target access data.

DRAWINGS

1 is a flow chart of a data caching method in accordance with an embodiment of the present invention;

2 is a schematic diagram of a data caching method according to an embodiment of the present invention;

FIG. 3 is a schematic diagram of step S102 in a data caching method according to an embodiment of the present invention; FIG.

4 is a schematic diagram of step S104 in a data caching method according to an embodiment of the present invention;

FIG. 5 is a schematic diagram of a data caching device according to an embodiment of the present invention; FIG.

6 is a schematic diagram of a data caching device in accordance with another embodiment of the present invention;

as well as

7 is a schematic diagram of a data caching device in accordance with another embodiment of the present invention.

detailed description

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. As shown in FIG. 1, a data caching method according to an embodiment of the present invention includes the following steps. Step S101: Receive a data request message sent by the user terminal. In this step, the user terminal and the server use the data request message to access the data, wherein the user terminal may be a mobile phone, a tablet personal computer, a laptop computer, a personal digital assistant (Personal) Digital Assistant (PDA), Mobile Internet Device (MID) or Wearable Device. The storage mode of the server is distributed storage, and includes a cache device and a storage device.

As shown in Figure 2, the cache device uses devices with faster read and write speeds, such as Solid State Drives (SSD), while the storage device uses devices with slower read and write speeds, such as Hard Disk Drive (HDD). .

The data caching method according to an example of the present embodiment separates cold data (data having a small number of accesses) and hot data (data having a large number of accesses), that is, storing the hot data in the SSD and storing the cold data in the In the HDD, based on a server's Hot Spot Detection (HOSD) module, control of data transmission between the cache device and the storage device is performed. It should be noted that, in order to ensure the stability of the data request between the user terminal and the server, data transmission between the user terminal and the server may be performed through a public network, and the server is internally configured through a cluster network. The data transfer between the cache device and the storage device to implement data flow between the cache device and the storage device.

Step S102: If it is detected that the cache device does not include the target access data requested by the data request message, the target access data in the storage device is sent to the user terminal. In this step, as shown in FIG. 3, the server (not shown) receives the data request message sent by the Objecter module in the user terminal, and determines the requested target access data based on the data request message, and then accesses the target access data. Compare with the data in the cache device. If the cache device does not include the target access data, the target access data in the storage device is transmitted to the user terminal, thereby reducing the impact of the cache operation on the I/O delay. The cache device may include a Filter module, a Promotion module, and an Agent module. The Promotion module is responsible for transmitting the target access data from the storage device to the cache device, and the Agent module is responsible for transmitting the dirty data (ie, the modified data) in the cache device to the storage device. The device or the cold data in the cache device (ie, the data with less access times) is used, thereby improving the utilization of the storage resource and the data access hit rate of the user terminal.

In an example of the embodiment, step S102 further includes: if it is detected that the cache device includes the target access data requested by the data request message, sending the target access data in the cache device to the user terminal. .

Step S103: Extract parameter information of the target access data in the storage device, and determine whether the parameter information of the target access data matches the preset parameter condition. In this step, the parameter information may include the number of accesses, and may also include both the number of accesses and the access time. If the parameter information is the number of accesses, it is determined whether the number of accesses is greater than or equal to a preset first threshold, wherein the preset first threshold may be 3, 5, 6, or the like.

In addition, if the parameter information includes the number of accesses and the access time, it is determined whether the number of accesses of the target access data is greater than or equal to a preset second threshold and whether the access time of the target access data is within a preset period. Here, the preset second threshold may be 3 times, 5 times, 6 times, or the like. In an example of the embodiment, the access time of the target access data is within a preset period, and the time interval between the time when the target access data was last accessed and the current time is within a preset period. In another example of the embodiment, the access time of the target access data is within a preset time period, and may indicate that the time when the target access data was last accessed falls within a preset time period. The preset period may be, for example, one hour, one day, one week, or the like. By increasing the judgment of the access time of the data, it is possible to ensure the efficiency of the target access data.

Step S104: If the parameter information of the target access data matches the preset parameter condition, the target access data is transmitted to the cache device. In this step, the process of determining the parameter information of the target access data and the preset parameter condition is referred to step S103. By transmitting the target access data conforming to the preset parameter condition to the cache device to make the data stored in the cache device high-potential potential data, the problem of cache pollution of the cache device is effectively solved, and the use of the cache is improved. rate.

In an example of the embodiment, step S104 includes: if the parameter information of the target access data matches the preset parameter condition, transmitting the target access data stored in the storage device to the cache device.

In an example of the embodiment, steps S103 and S104 are performed asynchronously with steps S101 and S102. For example, step S103 and step S104 can be performed in a predetermined cycle. This allows the cache operation to occur asynchronously, avoiding the impact of cache operations on I/O latency.

In an example of this embodiment, the parameter information includes the number of accesses. If the parameter information of the target access data matches the preset parameter condition, the step of transmitting the target access data to the cache device includes: if the number of accesses of the target access data is greater than or equal to a preset first threshold, transmitting the target to the cache device The data is accessed, wherein the first threshold may be 3, 5, 6 or the like. In this example, through the above steps, the frequently accessed data can be transmitted to the cache device so that the user terminal directly accesses the cache device, and the infrequently accessed data remains in the storage device, thereby reducing the cache device and the storage device. The overhead of data flow between. Since the data stored in the cache device is frequently accessed data, the cache pollution can be reduced.

In another example of this embodiment, the parameter information includes both the number of accesses and the access time. If the parameter information of the target access data matches the preset parameter condition, the step of transmitting the target access data to the cache device includes: if the number of accesses of the target access data is greater than or equal to a preset second threshold and the access time of the target access data During the preset period, the target access data is transmitted to the cache device. By increasing the judgment of the access time of the data, it is possible to further ensure the efficiency of the target access data.

In some embodiments, the data caching method further includes: detecting a cache occupancy rate of the cache device after the step of transmitting the target access data to the cache device; and clearing the cache if the cache occupancy rate is greater than or equal to a preset third threshold value The number of accesses in the device is less than or equal to a predetermined fourth threshold and/or the modified data in the cache device is transmitted to the storage device, wherein the third threshold may be 80%, 85%, 90%, or the like. In this embodiment, the cache device can have redundant storage space for other data access through the above steps. The data whose access count is less than or equal to the preset fourth threshold is cold data, and the modified data in the cache device is dirty data. When data replacement is performed, the number of accesses and access times of the data can be comprehensively considered to ensure that the data blocks replaced from the cache device have a low hit potential (ie, are unlikely to be accessed again).

The implementation process is shown in Figure 4. It is mainly composed of four linked lists, namely MRU, MFU, MRUG and MFUG. One end of the MRU linked list is the MRU end, and the other end is the LRU end. The MFU end of the MFU linked list is the MFU end and the other end is the LFU end. When the data just enters the cache device, the data is first put into the MRU queue, and the MRU queue is a finite sequence sorted according to the access time of the data block. When a new data enters the MRU queue again, the data block at the LRU end of the MRU queue (ie, the block of data that has not been accessed for the longest time) will be replaced. If a data block in the MRU queue is accessed twice before being replaced, the data is placed into the MFU end of the MFU queue.

The MFU linked list is also a finite sequence that is sorted according to the access time of the data. The difference is that each time a second hit occurs, the corresponding data in the MFU linked list is placed in the MFU header (MFU end). If there is data to enter the cache, and the number of data blocks in the cache has reached the previously set threshold, the elements are deleted from the LRU and LFU, and the corresponding metadata information is sent to the MFUG queue and the MRUG queue respectively.

The MFUG and MRUG do not store data blocks, only the access records of the data blocks. The data block in the MFU linked list is sent to the MFUG linked list, and the storage space occupied by the data block is released. If the data block to be released is in the MRU linked list, the data block is deleted from the MRU linked list and sent to the MRUG linked list.

Both the MFUG and MRUG linked lists are first in, first out (FIFO) linked lists with a threshold of x. When the length of the linked list increases to equal x, the oldest access record in the linked list is deleted. When the data block is accessed again, if the data block is in the MRUG or MFUG linked list, the database is read from the storage pool and the data block is reinserted into the MRU or MFU. The HOSD module can dynamically adjust the number of elements that should be included in the MRU and MFU linked lists based on how many false hits occur in the MRUG or MFUG list. The adjustment method is as follows: When a false hit occurs in the MRUG linked list, the length of the MRU linked list is increased by 1, and the length of the MFU linked list is decreased by 1. When a pseudo hit occurs in the MFUG list, the MFU list length is increased by one, and the MRU list length is decreased by one. This ensures that the total length of the MRU and MFU linked lists in the cache remains constant.

In some embodiments, the method further comprises the steps of: redundantly backing up cache information in the memory of the cache device to the persistent storage device of the cache device after the step of transmitting the target access data to the cache device; and if detecting When a node failure or a system crash occurs in the cache device, the persistent cache information in the cache device is restored to the cache device. In this embodiment, the cache metadata information in the memory of the cache device is packaged into an object for backup at regular intervals. The backup data is written to the persistent storage device of the cache device in a checkpoint manner by the write logic in the storage device, wherein the checkpoint is only executed periodically and does not bring load to the system. When the cache metadata information is lost due to a node failure or system crash in the cache device, the data backed up in the cache device's persistent storage device is restored to the cache device to ensure that in the event of a node failure or system crash It still works, ensuring the system's fault tolerance.

With the data caching method according to the embodiment of the present invention, the cache device stores only data satisfying the condition of the preset parameters (for example, data with a large number of accesses), and does not allow the data with less access times to occupy the storage space of the cache device, thereby improving The utilization of storage resources and the data access hit ratio of the user terminal.

As shown in FIG. 5, the data cache device 500 according to an embodiment of the present invention includes: a receiving module 501 for receiving a data request message sent by a user terminal; and a sending module 502, which detects whether the cache device includes a data request message. The target accesses the data, and if it detects that the cache device does not include the target access data requested by the data request message, transmits the target access data in the storage device to the user terminal; and the extraction module 503 is configured to extract the target access in the storage device Parameter information of the data, and determining whether the parameter information of the target access data matches the preset parameter condition; and the transmission module 504, if the parameter information of the target access data matches the preset parameter condition, the transmission module 504 transmits to the buffer device Target access data.

In some embodiments, the parameter information includes the number of visits. If the number of accesses to the target access data is greater than or equal to the preset first threshold, the transmission module 504 transmits the target access data to the cache device.

In some embodiments, the parameter information includes the number of visits and the access time. If the number of accesses of the target access data is greater than or equal to the preset second threshold and the access time of the target access data is within the preset period, the transmission module 504 transmits the target access data to the cache device.

In some embodiments, the sending module 502 is further configured to: if the cache device is detected to include the target access data requested by the data request message, send the user in the cache device to the user terminal Target access data.

In some embodiments, as shown in FIG. 6, the data cache device 500 further includes: a detecting module 505 for detecting a cache occupancy rate of the cache device; and a processing module 506 if the cache occupancy rate is greater than or equal to a preset The third threshold, the processing module 506 clears the data in the cache device that the number of accesses is less than or equal to the preset fourth threshold and/or transmits the modified data in the cache device to the storage device.

In some embodiments, as shown in FIG. 7, the data cache device 500 further includes: a backup module 507 for redundantly backing up cache information in the memory of the cache device to the persistent storage device of the cache device; and a recovery module 508. If a node failure or system crash occurs in the cache device, the recovery module 508 restores the cached information in the cache device to the cache device.

In some embodiments, data caching device 500 is included in a caching device. In this case, the cache device may include hardware that performs the functions of the respective modules.

In some embodiments, data caching device 500 is a device that is separate from the caching device and the storage device.

It should be noted that the data caching device 500 can be utilized to implement various steps of the data caching method according to the present invention, and the utilization ratio of the storage resource and the data access hit ratio of the user terminal are improved.

One of ordinary skill in the art will appreciate that all or part of the steps and/or modules of the above-described embodiments may be implemented in hardware associated with program instructions, and program instructions may be stored in a computer readable medium. The program instructions cause a computer to perform a data caching method in accordance with the present invention. The computer readable medium can be, for example, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

Numerous modifications and changes may be made to the present invention without departing from the spirit and scope of the invention. Accordingly, the specification and drawings are to be regarded as

Claims

A data caching method includes the following steps:

Receiving a data request message sent by the user terminal;

If it is detected that the cache device does not include the target access data requested by the data request message, transmitting the target access data in the storage device to the user terminal;

Extracting parameter information related to the target access data in the storage device, and determining whether the parameter information matches a preset parameter condition;

And if the parameter information matches the preset parameter condition, transmitting the target access data to the cache device.
The method of claim 1 wherein

The parameter information includes the number of accesses, and

If the parameter information matches the preset parameter condition, the step of transmitting the target access data to the cache device includes: if the number of accesses is greater than or equal to a preset first threshold, then The cache device transmits the target access data.
The method of claim 1 wherein

The parameter information includes the number of accesses and the access time, and

If the parameter information matches the preset parameter condition, the step of transmitting the target access data to the cache device includes: if the number of accesses is greater than or equal to a preset second threshold and the access time The target access data is transmitted to the cache device during a preset period.
The method according to any one of claims 1 to 3, wherein after the step of transmitting the target access data to the cache device, the method further comprises:

Detecting a cache occupancy rate of the cache device;

If the cache occupancy is greater than or equal to a preset third threshold, clearing data of the number of accesses in the cache device that is less than or equal to a preset fourth threshold and/or transmitting the cache device to the storage device Modified data in .
The method according to any one of claims 1 to 3, wherein after the step of receiving a data request message sent by the user terminal, the method further comprises:

Redundantly backing up cache information in the memory of the cache device to a persistent storage device of the cache device;

If it is detected that a node failure or a system crash occurs in the cache device, the persistent cache information in the cache device is restored to the cache device.
The method according to any one of claims 1 to 3, wherein after the step of transmitting the target access data to the cache device, the method further comprises:

If it is detected that the cache device includes the target access data requested by the data request message, the target access data in the cache device is sent to the user terminal.
A data caching device comprising:

a receiving module, configured to receive a data request message sent by the user terminal;

a sending module, configured to: if it is detected that the cache device does not include the target access data requested by the data request message, send the target access data in the storage device to the user terminal;

An extraction module, configured to extract parameter information related to the target access data in the storage device, and determine whether the parameter information matches a preset parameter condition;

And a transmission module configured to transmit the target access data to the cache device if the parameter information matches the preset parameter condition.
The data caching device according to claim 7, wherein

The parameter information includes the number of accesses; and

The preset parameter condition is that the number of accesses is greater than or equal to a preset second threshold.
The data caching device according to claim 7, wherein

The parameter information includes a number of accesses and an access time;

The preset parameter condition is that the number of accesses is greater than or equal to a preset second threshold and the access time is within a preset period.
The data caching device according to any one of claims 7 to 9, further comprising:

a detecting module configured to detect a cache occupancy rate of the cache device;

a processing module, configured to: if the cache occupancy rate is greater than or equal to a preset third threshold, clear data that is less than or equal to a preset fourth threshold in the cache device and/or to the storage device Transmitting the modified data in the cache device.
The data caching device according to any one of claims 7 to 9, further comprising:

a backup module configured to redundantly back up cache information in the memory of the cache device to a persistent storage device of the cache device;

And a recovery module configured to restore persistent cache information in the cache device to the cache device if a node failure or a system crash in the cache device is detected.
The data caching device according to any one of claims 7 to 9, wherein the transmitting module is further configured to: if it is detected that the cache device includes the target access data requested by the data request message, Transmitting the target access data in the cache device to the user terminal.
A computer readable medium storing program instructions for causing a computer to perform the method of any one of claims 1 to 6.